Existing recommendations for treating vitamin D
deficiency in children with cystic fibrosis are
too low to cover the serious need, leaving most at high
risk for bone loss and rickets, according to
researchers at
Johns
Hopkins Children's Center.

In results of their investigation, published in the
October issue of The Journal of Pediatrics,
the Johns Hopkins team found that nearly half the 262
children with CF in the study were vitamin D
deficient, and the majority of these remained persistently
so, despite getting restorative doses equal
to or higher than the recommendations set by the Cystic
Fibrosis Foundation.

As a result of the findings, Johns Hopkins already has
amended its treatment protocol and now
treats both adult and pediatric CF patients who have
vitamin D deficiency with 50,000 IU daily for
four weeks. Growing children with CF are especially
vulnerable to vitamin D deficiency because a
hallmark of their condition is poor absorption of nutrients
and malnutrition. CF, a genetic disorder, is
marked by the body's inability to transport chloride in and
out of cells, causing mild to life-threatening
complications, including recurrent and severe lung
infections and delayed growth. The Cystic Fibrosis
Foundation defines vitamin D deficiency in patients as
levels lower than 30 nanograms per milliliter and
recommends that patients who are vitamin D deficient
receive a weekly dose of 50,000 IU of
ergocalciferol, a form of vitamin D.

"These findings are a big wake-up call not only
because they show that many children with CF
are lacking vitamin D but also because the deficiency
persists even in those children who are treated
with weekly doses twice or three times as high as the
current recommendations," said Johns Hopkins
Children's Center lung specialist Deanna Green, who led the
research. "Clearly there is an urgent need
to find more effective ways to restore healthy vitamin D
levels."

In the meantime, investigators said, doctors caring
for patients with CF should think about
increasing the vitamin D intake beyond the current
recommendations in those who are vitamin D
deficient. They should also check vitamin D levels at least
once a year in all CF patients and more
frequently in those with abnormally low levels. In the
current study of CF patients treated at Johns
Hopkins between 2003 and 2006, investigators found that 86
percent were vitamin D deficient in
2003, 50 percent in 2004, 54 percent in 2005 and 46 percent
in 2006.

Comparing different weekly intakes of ergocalciferol,
the Johns Hopkins team found that the
currently recommended 50,000 IU per week for eight weeks
was effective in only 33 percent of the
patients with vitamin D deficiency, while increasing the
therapy to twice a week was effective in 26
percent of patients. Delivering the same dose three times a
week corrected the deficiency in just 43
percent of children.

Vitamin D levels appeared to follow fluctuations in
seasonal sun exposure, dropping sharply in
the fall and winter and peaking during spring and summer.
Vitamin D deficiency was worst during the
fall, with 83 percent of patients testing deficient, while
only 41 percent were vitamin D deficient in
the summer. Sun exposure is critical for vitamin D
synthesis and production. Some doctors recommend
sun exposure twice a week for up to 30 minutes at a time,
but the debate is ongoing because sun
exposure without protection increases the risk of skin
cancer.

"Clearly we haven't established an optimal dose for
treating vitamin D deficiency, and more
research is needed to do so," said senior researcher Peter
Mogayzel, director of the Johns Hopkins
Children's Center Cystic Fibrosis Center. "But what we know
for sure is that the current
recommendations are too low, and doctors should treat their
patients with vitamin D deficiencies more
aggressively," he said.

New therapies and earlier diagnosis have led to more
and more CF patients living longer and well
into adulthood, which means that vitamin D deficiency will
be increasingly important for CF patients as
they age.

"It is a testament to the advances we've made in
treating CF, but as more and more patients
survive and live longer, they will begin to face chronic
conditions usually seen in healthy adults,"
Mogayzel said. "If we do not treat vitamin D deficiency
early on, bone disease and osteoporosis will be
increasingly a problem in the aging CF population." The
findings come on the heels of another Johns
Hopkins study showing that low levels of vitamin D
increased the overall risk of death by 26 percent in
the general population.

Other investigators in the study were Kathryn Carson,
Amanda Leonard, Erin Davis, Beryl
Rosenstein and Pamela Zeitlin, all of Johns Hopkins.